The overall goal of this project is an understanding of the intermediary metabolism of gastropod vectors of animal parasites and how this metabolism may be modified to support their various modes of life. The specific objective for this project period is an understanding of the energy-yielding pathways utilized in different physiological states. These include the active, possibly aerobic state; the estivating, possibly anaerobic state; and the anoxic state. Specific investigations to be made on animals in these different states include mitochondrial function (substrates oxidized, nature of electron transport chain, mechanism for generation of high-energy phosphate) and major pathways of carbohydrate metabolism (glycolytic pathway, tricarboxylic acid cycle and modifications thereof) and their regulation. The metabolism of those fatty acids and amino acids directly related to these pathways will also be of interest. For these investigations, contemporary biochemical methods will be used.